JPH08502080A - Fiber and film - Google Patents

Abstract

  (57) [Summary] The fibers or films of the water-absorbing, water-insoluble fibrous material comprise cross-linked copolymers formed from 50 to 95% by weight of ethylenically unsaturated carboxylic xyl monomer and 5 to 50% by weight of copolymerizable erenically unsaturated monomer. Has a matrix. The matrix comprises regions of dispersed polymeric material, the matrix copolymer and the dispersed polymeric material being immiscible with each other and chemically substantially non-reactive under ambient conditions. The fiber or film can be made by extruding a solution or dispersion of a dispersed polymeric material in a matrix copolymer solution in the uncrosslinked state into a gaseous environment.

Description

DETAILED DESCRIPTION OF THE INVENTION Fibers and Films Field of the invention The present invention relates to fibers and films of water-absorbing, water-insoluble materials. Water-absorbing and water-insoluble materials are used in many absorbent products, especially products for absorbing aqueous body fluids, such as baby diapers, incontinence pads, sanitary napkins and tampons, and spills of aqueous fluids. It is useful as a wiping material for wiping. Most water-absorbing, water-insoluble materials are available only in powder form. There is a problem in holding absorbent powders in desired locations in absorbent products, such as diapers. Whether staple fibers or continuous fibers, the fibers can be more effectively held in place by incorporation into the fabric, and the fibers or films are also effective in other products. Can be held in place. Background technology EP-A-268498 describes forming a substantially linear polymer from a water-soluble ethylenically unsaturated monomer blend containing carboxyl and hydroxyl monomers, and subsequently in a linear polymer. A water-absorbing, water-insoluble polymer fiber, film, coating, tie layer or foam made by reacting carboxyl and hydroxyl monomers to form intercrosslinks within the polymer is described. EP-A-269393 discloses dry extrusion of a solution of a substantially linear polymer formed from a water soluble blend of monoethylenically unsaturated monomers containing a plasticizing monomer and evaporation of the solvent. , A water-absorbing, water-insoluble, cross-linked polymeric fiber or film manufactured by The fiber or film is further plasticized, drawn and then crosslinked. EP-A-342919 describes films or fibers produced by extrusion and drawing from polymers of water-soluble ethylenically unsaturated monomers containing ionic monomers. The counterion lubricious compound is absorbed on the surface of the fiber or film before or during drawing. EP-A-397410 describes water-soluble linear polymers of carboxylic acid monomers such as acrylic acid and hydroxyl monomers. It may be shaped as a fiber or film by extrusion of an aqueous solution of the polymer and then crosslinked to form crosslinks between carboxyl and hydroxyl groups. GB-A-2082614 describes a dry, solid, water-swellable absorbent comprising a blend of a water-insoluble absorbent polymer and an extender material, said polymer comprising: It can be covalently crosslinked or ionically bonded to anionic polyelectrolytes, and said extender material is an uncrosslinked derivative, starch, montmorillonite clay, attapulgite clay, sericite, talc, silica and mixtures thereof. Selected from the group consisting of. This specification does not disclose how the blend can be used as a film, cell film, powder or fiber, but how a blend of water insoluble polymer and extender can be made into fibers. Disclosure of the invention According to the present invention, a fiber or film of a water-absorbing, water-soluble fibrous material is formed from 50 to 95% by weight of ethylenically unsaturated carboxylic acid monomer and 5 to 50% by weight of copolymerizable ethylenically unsaturated monomer. A matrix of cross-linked copolymers, the matrix comprising regions of dispersed polymeric material, the matrix copolymer and the dispersed polymeric material being immiscible with each other and, at ambient conditions, substantially, It is non-chemically reactive. The dispersed phase polymeric material may be water soluble. The polymeric material of the dispersed phase may be self-crosslinking and optionally crosslinkable with the matrix material. The fiber or film is extruded a solution or dispersion of a polymeric material in a matrix copolymer solution in an uncrosslinked state into a gas phase environment, where the solvent is removed to form a fiber or film, And, subsequently, formed by cross-linking the matrix copolymer and optionally the dispersed polymeric material. The fiber or film may be drawn after it has been formed, preferably before the crosslinking system is activated. The cross-linking system can be a system that is activated by irradiation, for example UV light, but preferably it is heat activated, in which case the temperature predominantly found during the earlier stages of stretching and processing. The crosslinking rate at should be such that there is substantially no crosslinking between these steps. By this means it is possible to optimize the stretching of the fiber or film while the polymer is linear and then fix the polymer in its stretched configuration by crosslinking. Preferably, the uncrosslinked matrix copolymer is substantially linear. It is formed from a blend of ethylenically unsaturated monomers, and it must be chosen so that the final crosslinked copolymer is water absorbing. Methods for selecting monomers for this purpose are known and can be found, for example, from the above-mentioned European patent application EP-A-3 97410. Generally, the blend of ethylenically unsaturated monomers is an anionic blend, and usually contains carboxylic acid monomers, and preferably also nonionic monomers. The monomers used in the present invention may be allylic, but are usually vinylic, most preferably acrylic monomers. The preferred carboxylic acid monomer is methacrylic acid or acrylic acid, but maleic acid or its anhydride, itaconic acid or any other conventional ethylenically unsaturated carboxylic acid or its anhydride is also suitable. The copolymer may optionally additionally contain monomer units derived from ethylenically unsaturated sulphonic acids, for example 2-acrylamido-2-methylpropanesulphonic acid or allylsulphonic acid. The carboxylic acid and sulfonic acid monomer units may be present in the final copolymer in the form of the free acid or water-soluble salts, suitable salts being formed with ammonia, amines or alkali metals. The ratio of salt and free acid groups can be adjusted after the formation of the crosslinked polymer or after or before the polymerization of the linear polymer. Generally, in the final copolymer (often in the monomers used to form the linear copolymer), the molar ratio of free acid groups to carboxylic acid groups of the alkali metal or other salt is 1: 1 to 1:10. Is. This ratio is usually at least 1: 2 and often at least 1: 3. It is usually lower than 1: 6 and often lower than 1: 5. When the cross-linking reaction involves reaction with carboxylic acid groups, it is usually preferred that at least a certain number of carboxylic acid groups should be present as the free acid before cross-linking occurs. For example, for this purpose, it may be suitable that 10-75%, preferably 25-75% of the acid groups are in the free acid form before crosslinking takes place. Linear copolymers can generally be prepared by the polymerization of carboxylic acid monomers (in the free acid or salt form), but it is also possible to prepare the copolymer by subsequent polymerization of the monomers which can be reacted to form carboxylic acid monomers. It is possible. For example, the carboxylic acid groups to be present (in the free acid or salt form) in the cross-linked copolymer may first be present in the linear copolymer in the form of hydrolyzable ester groups such as methyl ester groups. , Which can then be hydrolyzed to give carboxylic acid (free acid or salt) groups during the formation of the linear copolymer. The copolymerizable ethylenically unsaturated monomer for the matrix copolymer can be a water soluble ethylenically unsaturated monomer, for example acrylamide, or a water insoluble monomer, for example an olefin such as isobutylene, an aromatic An ethylenically unsaturated monomer such as styrene or substituted styrene, an alkyl ester of acrylic or methacrylic acid, such as methyl or ethyl acrylate or methacrylate, butyl acrylate or methacrylate or 2-ethylhexyl acrylate or methacrylate, vinyl acetate or acrylonitrile. it can. One or more copolymerizable monomers may be present. Monomers that will provide groups for internal cross-linking with carboxylic acid groups (as discussed below) are usually included. Other nonionic monomers that may be used include ethylenically unsaturated monomers, which have the formula A _m B _n A _p R has a pendant group, where B is ethyleneoxy, n is an integer of at least 2, A is propyleneoxy or butyleneoxy, and m and p are each an integer smaller than n, preferably Is less than 2 and most preferably 0, R is a hydrophobic group containing at least 8 carbon atoms, and is described in more detail in EP-A-213799. Comonomers are generally present in an amount of at least 5%, more preferably at least 10%, based on the weight of the monomers used to form the copolymer, and they are generally present in an amount up to about 50% by weight. May be present in less than 45% by weight. The substantially linear copolymer can be formed from the monomer blend in any conventional manner. It can be preformed and then dissolved to form a polymer solution. For example, if the monomer blend is water soluble, it can be made by reverse phase polymerization, or the blend can be made, for example, by water-in-oil emulsion polymerization if it is water insoluble at low pH. . However, this can lead to the risk that the copolymer can be contaminated with surfactants, which is undesirable. Therefore, preferably the copolymer is produced by aqueous solution polymerization or other solution polymerization processes. It may be dried before further processing, but is not preferred. Generally, it is formed by solution polymerization in a solvent, in which it is extruded (usually water). The polymerization can be carried out by conventional methods in the presence of conventional initiators and / or chain transfer agents to provide the desired molecular weight. The concentration of the copolymer to be extruded in solution is generally in the range of 5 to 50% and will be selected with consideration of the molecular weight of the copolymer to provide a solution having a convenient viscosity for extrusion. The solution may be extruded through a spinneret, suitably a spinneret of the type commonly used in the manufacture of synthetic fibers. The concentration of the copolymer is usually at least 15% by weight, values of 30 to 45%, for example 35% to 40% are often particularly suitable. The extruded solution or dispersion can have a viscosity at 20 ° C., for example, up to a low of 20,000 mPa.s, but generally the viscosity is at least 70,000 mPa.s and usually at least 100,000 mPa.s. .s, and often at least 120,000 mPa.s. It can be up to 150,000 mPa.s, or even 200, OO0 mPa.s. Higher values are generally not needed. All of these viscosities are measured using a Brookfield RVT spindle 7 at 20 rpm at 20 ° C. Viscosity is also desirably relatively high, typically at elevated temperatures, for example, extrusion temperatures above 80 ° C. but below the boiling point of the copolymer solution or dispersion. Preferably, the solution or dispersion is at least 5000 or 10,000 mPa.s at 80 ° C, most preferably at least 20,000 mPa.s. For example, it can be 50,000-100,000 mPa.s. These values are extrapolated from those obtained using the Brookfield RVT viscometer spindle 7 at 20 rpm in the temperature range somewhat below 80 ° C. The molecular weight of the extruded linear copolymer may be as low as, for example, 50,000 or 100,000, but is preferably above 300,000, most preferably above 500,000. For example, it can be more than 1,000,000. The solvent of the extruded solution or dispersion is usually water, but can be methanol or other suitable organic solvent, or it can be a blend of water and organic solvent. The solvent must be volatile to allow rapid evaporation after extrusion. The gaseous environment in which the solution is extruded is preferably hot air. Upon formation of the fibers, hot air can be included in cells of the type commonly used for dry spinning, or flash spinning can be used. The extruded fiber can be wound as a yarn or toe on a conventional spinning machine, such as a godet. Conventional spin finishes, which are preferably non-aqueous, are usually applied to the fibers before they are wound. Upon formation of the film, the aqueous solution or dispersion is extruded onto a support surface, such as a heated rotary drum, through a heated gas environment, such as hot air, such as through a slit die or annular die. You can The surface of this support has release properties. Drying of the film is continued on the drum, and the film is stripped from the drum and wound into rolls. The moisture content of the film as it is wound is generally in the range of 8-25%, most preferably 10-20%, based on the weight of the dry film. It is preferred to stretch the fiber or film before collecting the fiber or film. Stretching is performed by having the speed of the collecting device, for example, the take-off godet, higher than the extrusion speed of the polymer solution (the linear speed of the polymer solution passing through the outlet capillary of the spinneret or die). The ratio of take-off speed to extrusion speed is generally up to 10: 1, but is preferably in the range 2-8: 1, most preferably in the range 3-6: 1. The final fiber diameter preferably corresponds to a weight of less than 20 decitex / filament, for example in the range of 2-15 decitex / filament. This is the decitex after drawing, and if draw is used, the decitex / filament after the initial extrusion may be higher than the above range. If stretching is used, it is done before crosslinking. The linear copolymer for the matrix copolymer is crosslinked after extrusion. Crosslinking can be done by reaction to the backbone of the linear copolymer, but is preferably done by crosslinking through pendant groups provided by one or more monomers polymerized to form the linear copolymer. The cross-linking can be, for example, an ionic cross-linking resulting from exposing the linear copolymer to any of the known ionic cross-linking agents, for example a polyvalent aluminum compound such as aluminum sulfate. Organic compounds may be used instead of inorganic compounds to provide cross-linking. However, preferably the crosslinks are covalent bonds between pendant groups in the linear copolymer. Covalent cross-linking generally occurs as a result of the formation of ester, amide (or imide) or urethane groups by reaction of the carboxylic acid groups after extrusion of the copolymer. Ester groups are preferred. The crosslinking reaction may be carried out with an external crosslinking agent. Various systems for externally crosslinking copolymers are described in European Patent Application EP-A-269393, and these can be used in the present invention. For example, carboxyl-functional linear copolymers are crosslinked with diisocyanates to form urethane crosslinks, or with polyamines such as ethylenediamine to form amide crosslinks, or polyfunctional containing hydroxyl and / or epoxide groups. It can be cross-linked with a sexing reagent to form an ester cross-link. However, preferably the polymer is internally crosslinked by reaction between the reactive groups within the extruded copolymer. Usually, carboxyl groups act as one type of reactive group and are reactive with hydroxyl, epoxide, amino or blocked isocyanate groups. Particularly preferred systems are described in detail in EP-A-268496. In these systems, the extruded copolymer is formed from a monomer blend that includes a monomer that provides a carboxylic acid group and a monomer that provides a hydroxyl group, wherein the hydroxyl group reacts with the carboxylic acid group to form carbon and oxygen. Ester bridges containing only atoms in the bond can be formed. Then, these carboxylic acid groups and hydroxyl groups react after extrusion to form the above-mentioned crosslinks. Generally, the carboxylic acid group is provided by acrylic acid or methacrylic acid, and the hydroxyl group is allyl alcohol, an epoxide-substituted vinyl monomer such as glycidyl methacrylate, or a hydroxyalkyl ester of vinylcarboxylic acid such as 2-hydroxyethyl acrylate. , 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate or 3-hydroxypropyl methacrylate, or a vinyl alcohol group. Another hydroxyl-containing monomer has the formula CHR ¹ = CR ² -Y-Ma-OH, where R ¹ Is hydrogen or carboxy, R ² Is hydrogen or methyl, Y is O, CH ₂ O or COO, M is alkyleneoxy, for example ethyleneoxy or 1,2-propyleneoxy, and a is an integer greater than l, preferably at least 5, EP-A-EP -As described in A-397410. Alternatively, the comonomer can include primary or secondary amine groups, such as 2-aminoethylmethacrylate, which react to form amide crosslinks, or isocyanate groups (to prevent crosslinks during extrusion. It must be a blocked isocyanate), for example 2-isocyanatoethylmethacrylate to form a urethane bond. Reference should be made to EP-A-268498 and EP-A-397410 for a complete disclosure of suitable materials and extrusion and cross-linking methods which can be used in the present invention. As mentioned above, heat-activated crosslinking is preferred. The temperature used to crosslink the fiber or film is, for example, 150 to 250 ° C., the temperature during extrusion and drawing is below the crosslinking temperature, preferably at least 30 ° C. below. Dispersed polymeric materials include, for example, starch or chemically modified starch; one or more cellulose ethers such as carboxymethyl cellulose; polyvinyl alcohol; polyacrylamide; polyvinylpyrrolidone; polyalkylene oxides; or polymers of unsaturated sulfonic acid esters. However, the composition is sufficiently different from the matrix copolymer to ensure immiscibility. Under the conditions used to crosslink the matrix copolymer, the dispersed polymer also may or may not be crosslinked depending on its chemistry. It is preferred that the dispersed polymer is crosslinkable, in which case a latent crosslinker, such as a crosslinker that is heat activated if the matrix copolymer is crosslinked by heat, may be incorporated during polymer manufacture. preferable. The dispersed polymeric material is preferably water soluble. A solution of the dispersed polymer in water is obtained by direct polymerization of one or more water-soluble monomers in water, by direct dissolution of the solid polymer in water, or by inverse emulsion polymerization followed by evaporation of the non-aqueous solvent. Or by a chemical reaction in a slurry or latex of a water-insoluble precursor polymer. An example of such a reaction is the hydrolysis of polyvinyl acetate to produce an aqueous solution of polyvinyl alcohol. Prior to extrusion, it is necessary to prepare a dispersion or solution of the polymer dispersed in the matrix copolymer solution. Dispersions are usually prepared by mixing an aqueous solution or emulsion of polymeric material with an aqueous solution of a matrix copolymer. The size of the dispersed polymer solution phase should preferably be small to ensure good extrusion continuity. Mixing can be done, for example, using a high shear mixer, ultrasonically, or mechanically by pumping the solution through a static mixer. Since the size of the dispersed phase will increase over time, it is preferred to extrude into fibers or films as soon as possible after mixing the solutions. Dispersion aids such as block or graft copolymers may optionally be included to improve the stability of the dispersion. The dispersed polymeric material can reduce the viscosity of the copolymer solution or can be selected to improve the properties of the fiber or film. For example, when it is polyvinyl alcohol, it changes the absorbency and retention properties of the fiber or film, or increases the flexibility of the fiber or film. Natural polymers such as starch or chemically modified starches can be used as the polymeric material dispersed to improve the biodegradability of the fiber or film. According to one aspect of the invention, the dispersed polymeric material improves the absorbency and retention properties of the fiber or film to liquids. Absorbency can be measured by the free swell test, in which 0.5 g of fiber is dispersed in 30 ml of aqueous liquid and left for 5 minutes. The aqueous liquid used is generally a 0.9% by weight saline solution, which is absorbed to the same extent as body fluids such as urine. The test can alternatively be performed with either tap water or deionized water, but the results shown below are for 0.9% saline solution. For all absorbency measurements, the fibers are conditioned at 65% relative humidity and 20 ° C before testing. The dispersion was then filtered through a sintered Mark 1 funnel with 100-160 micron pore size and left for 5 minutes or until the drip stopped. The water filtered through the funnel is weighed, and the weight of the water absorbed by the fiber is calculated by subtraction. In addition to the above test, the retention of an aqueous liquid, such as an aqueous salt solution, by a fiber or film after the application of pressure weighs the water that emerges after applying a pressure of about 3.4 KPa for 5 minutes or until the drip stops. It is measured by In a further test of absorption, the absorbency under load is measured by keeping the fiber or film in contact with 0.9% by weight saline solution for a weight of 1.7 MPa during the load. The presence of dispersed polymeric material in the fiber or film enhances the absorbency, retention or absorbency under load, as measured by these tests, or the fiber or film absorbs an aqueous fluid. Improves the dry feel of the gel formed later. The dispersed polymeric material also reduces the dependence of these properties of the fiber or film on the ionic salt concentration in the aqueous fluid. The proportion of dispersed polymeric material in the fiber or film is generally up to 20% by weight, based on the copolymer, for example up to 15% by weight, preferably up to 10% by weight. Generally, the proportion of dispersed polymeric material is at least 1% by weight to achieve a substantial effect. For many purposes, the proportion of dispersed polymeric material is up to 5% by weight, preferably at least 2% by weight. The particle size of the dispersed polymeric material in the fiber or film is, for example, up to about 20 or 25 microns, more usually up to 15 microns. When the proportion of dispersed polymeric material in the fiber or film is higher than 5% by weight, generally the size of the particles can be up to about half the diameter of the fiber or the thickness of the film, while, for example, below 10 microns. Relatively low particle sizes, preferably below 5 microns are preferred. Particle sizes smaller than 1 micron may be preferred. Polymer solutions containing dispersed polymeric materials can be converted to fibers (including filaments and fibrils) or films (including sheets and coatings) by evaporation of the solvent after shaping. The fibers produced can be further processed into milled fibers, yarns, webs, or nonwovens, knitted or non-woven fabrics. The water-absorbent, water-insoluble fibers or films of the present invention can be used in various products. It can be used, for example, in absorbent body products such as tampons, disposable diapers, sanitary napkins or incontinence pads. The absorbent fibers are preferably other fibers, such as cellulosic fibers, such as cotton or regenerated cellulosic fibers, including multi-limbed cellulosic fibers as described in EP-A-301874. Or used in combination with propylene or polyester fibers. The absorbent fibers are intimately mixed with the other fibers to form a web of mixed fibers, for example by carding or air laying the fibers. Alternatively, the absorbent fiber or film may be used, for example, as a layer of a nonwoven fabric of absorbent fibers sandwiched between layers of other fibers. The proportion of absorbent fibers in the blend with cellulose fibers for absorbent products is, for example, at least 5% by weight and up to 95% by weight, preferably at least 10% by weight and up to 50% by weight. . Absorbent fibers may also be used in absorbent products at similar contents in combination with fluff wood pulp or synthetic fiber pulp, such as polyolefin pulp. Yarn, woven or non-woven fabrics containing absorbent fibers can be used as a swellable material, which prevents the ingress of water into underground cables. Yarn or fabric tape or absorbent film can be used to wrap the cable or lie longitudinally on the cable. Absorbent fibers or films are used in many other applications of the type described in Research Disclosure, January 1992, such as filters, absorbent liners or mats for packaging, disposable wipes, shoe insoles or bed sheets, swellable gaskets or It can be used in seals, horticultural moisture retention mats, moisture retention packaging or swellable self-sealing stitch yarns. The invention is illustrated by the following example. Example 1 A 40 wt% solution of Goeshenol GL05 ™ poly (vinyl alcohol) was prepared at 70 ° C. This solution was added to a 38 wt% aqueous solution of a copolymer of 78 mol% acrylic acid (75% neutralized as sodium salt), 20 mol% methyl acrylate and 2 mol% hexapropylene glycol monomethacrylate. The suspension was added at 55-65 ° C and stirred with a paddle stirrer. A homogeneous dispersion was obtained after 2 hours and contained about 38% by weight solids and 2% by weight polyvinyl alcohol, based on total polymer. This dispersion was spun into filaments into cells through a spinneret. Here, water was evaporated from the filament. The temperature of the dispersion in the spinneret was 90-100 ° C. The cell was heated to 150 ° C. with a tube wall heater. The filament was wound at a speed of about 200 meters / minute, providing about 15 dtex of fiber. The resulting multifilament toe sample was crosslinked by heating in air under the conditions shown in Table 1. The free swell absorbency, retentivity and absorbency under load (AUL) of the resulting fibers were measured in each case by the methods described above. Table 1 Free swelling retention at 210 ° C AUL Crosslinking time g / gg / gg / g 6 minutes 49.2 32.2 26.8 8 minutes 46.2 31.7 24.2 10 minutes 39.3 24.9 21.5 12 minutes 39.8 25.2 23.8 Results are relatively high under load It has absorbability. At all degrees of cross-linking, the absorbency under load of the tested fibers was higher than that of similar fibers without polyvinyl alcohol, which also had a high free swell absorbency. The fibers appeared softer than similar fibers without polyvinyl alcohol. Example 2 The starch is dissolved in water and mixed with a solution of a copolymer of acrylic acid, methyl methacrylate and hexapropylene glycol monomethacrylate in a weight ratio of 60: 35: 5 in water to give 5% by weight of starch based on total polymer. A dispersion containing 38% by weight was prepared. The mixing conditions were the same as described in Example 1. The prepared dispersion was dry spun as described in Example 1. The spun filaments were crosslinked for 10 minutes at 200 ° C to produce superabsorbent filaments. The water absorbency and retention of the filament was similar to a similar filament without starch, and the filament of Example 2 had improved biodegradability.

[Procedure Amendment] Patent Act Article 184-8 [Date of submission] April 21, 1994 [Amendment content] 1) Specification International application specification page 2 (Specification translation page 2 page 23 line 23- DISCLOSURE OF THE INVENTION According to the present invention, a fiber or film of water-absorbing and water-soluble material comprises 50 to 95% by weight of ethylenically unsaturated carboxylic acid monomer and 5 to 50% by weight of copolymerizability. A matrix of cross-linked copolymers formed from ethylenically unsaturated monomers, the matrix comprising regions of dispersed polymeric material, the matrix copolymer and the dispersed polymeric material being immiscible with each other, and Substantially non-chemically reactive at ambient conditions. 2) Claims (Claims translated page 17) Claims 1. A fiber or film of water-absorbing, water-insoluble material, comprising a cross-linked copolymer formed from 50-95% by weight of ethylenically unsaturated carboxylic monomer and 5-50% by weight of copolymerizable ethylenically unsaturated monomer. A matrix, the matrix comprising regions of dispersed polymeric material, and the matrix copolymer and the dispersed polymeric material are miscible with each other and are chemically substantially non-reactive at ambient conditions. A fiber or film characterized by that. 2. The fiber or film according to claim 1, wherein the dispersed polymeric material is a water-soluble polymer. 3. The fiber or film according to claim 1, wherein the dispersed polymeric material is crosslinked. 4. The dispersed polymeric material is starch or a chemically modified starch, and the fiber or film has an improved biodegradability as compared to the fiber or film formed solely from the matrix copolymer. The fiber or film according to claim 1. 5. Characterized in that the dispersed polymeric material is polyvinyl alcohol and that the fiber or film has improved absorbency under load and / or increased flexibility as compared to the fiber or film formed solely from the matrix copolymer The fiber or film according to claim 1 or claim 2. 6. Fiber or film according to any of claims 1 to 3, characterized in that the dispersed polymeric material is a cellulose ether, polyalkylene oxide or unsaturated sulphate ester polymer. 7. The dispersed polymeric material is 1 to 1 of the dry weight of the fiber or film.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI C08L 33/02 LHR 8619-4J D01D 5/04 7199-3B D01F 6/36 7199-3B 6/52 7199-3B

Claims (1)

[Claims]   1. A fiber or film of a water-absorbing and water-insoluble fibrous material, which is ethylene-based Unsaturated carboxyl monomer 50-95% by weight and copolymerizable ethylenic unsaturation With a matrix of crosslinked copolymer formed from 5 to 50% by weight of monomer The matrix comprises regions of dispersed polymeric material, and the matrix And the dispersed polymeric material are miscible with each other and Fibers or fills characterized by being substantially non-reactive chemically under conditions M   2. Claims characterized in that the dispersed polymeric material is a water-soluble polymer. The fiber or film according to Box 1.   3. Claim 1 characterized in that the dispersed polymeric material is crosslinked The described fiber or film.   4. The dispersed polymeric material is starch or chemically modified starch And a fiber or film in which the fiber or film is formed only from the matrix copolymer Has an improved biodegradability compared to a film. The fiber or film according to.   5. The dispersed polymeric material is polyvinyl alcohol, and the fibers or fibers The film is compared to a fiber or film formed only from matrix copolymers. Characterized by having improved absorbency under load and / or increased flexibility The fiber or film according to claim 1 or claim 2.   6. The dispersed polymeric material may be cellulose ether, polyalkylene oxide or Is an unsaturated sulfuric acid ester polymer, any one of claims 1 to 3 characterized in that The fiber or film described therein.   7. Dispersed polymeric material present at 1-10% by dry weight of fiber or film In any one of Claims 1-6 characterized by performing The described fiber or film.   8. Dispersed polymeric material is present up to 5% of the dry weight of the fiber or film The fiber or film according to claim 7, wherein:   9. Characterized in that the matrix copolymer is crosslinked by ester crosslinking The fiber or film according to any one of claims 1 to 8.   10. Low amount of copolymerizable ethylenically unsaturated monomer in matrix copolymer Both partially consisting of hydroxyl-functional or epoxide-functional comonomers, and The ester crosslinks with the carboxylic acid groups from the carboxyl monomer and the copolymerizable monomer From a hydroxyl group or an epoxide group from the The fiber or film according to claim 9, wherein:   11. A method for producing a fiber or film defined in any one of claims 1 to 10. Of a solution or dispersion of polymeric material in matrix copolymer solution. Extruded in a crosslinked state into a gaseous environment, where the solvent is removed to remove the fiber or film. Formed and then matrix copolymer and optionally dispersed poly A method of crosslinking a mer material.   12. Claims characterized in that the matrix copolymer solution is an aqueous solution The method according to range 11.   13. The concentration of the matrix copolymer in the aqueous solution is 30-45% by weight 13. The method according to claim 12, characterized in that   14. The boiling point of the solution or dispersion, above 80 ° C, of the copolymer solution or dispersion Any of claims 11-13 characterized in that it is extruded at a lower temperature. The method described in.   15. The solution or dispersion is at least 20,000 mPa.s at 80 ° C. 15. The method according to claims 11-14, having a viscosity of.   16. The solution or dispersion is extruded through a spinneret to form fibers. The method according to any one of claims 11 to 15, which is characterized.   17． Heating the fiber or film at a temperature in the range of 150 ° C to 250 ° C for crosslinking The method according to claims 1 to 16, wherein the method is performed by   18. Characterized in that the fiber or film is stretched before the crosslinking of the copolymer The method according to any one of claims 11 to 17.